node.js - mongodb怎么对分组，不要统计

Question

mongo.getCollection('t_app').aggregate([
        {
            $group: {
                _id: {
                    FuncName: "$FuncName",
                    Platform: "$Platform",
                    UseDateTime:{  $dateToString: { format: "%Y-%m-%d", date: "$UseDateTime" }}
                }
            }
        }
    ]

上面只是一个构想。。。，我想根据这些key的字段要求，进行分组，，不需要统计，完整的应该怎么写？

Answer 1

$push

Just push the result into the array.

mongo.getCollection('t_app').aggregate([
        {
            $group: {
                _id: {
                    FuncName: "$FuncName",
                    Platform: "$Platform",
                    UseDateTime:{  $dateToString: { format: "%Y-%m-%d", date: "$UseDateTime" }}
                }，
                result : {$push : "$Platform"}
            }
        }
    ]